Flow rate regulators exist in a variety of designs. They usually include an annular restrictor, which is made of an elastic material and delimits a control gap that changes under the pressure of the fluid flowing between itself and a wall of the housing. That is, as the pressure rises, the restrictor is pressed progressively into regulating profiles which are formed on a housing wall that is constructed either as a central regulating core or as an outer circumferential wall. Since the control gap contracts as the fluid pressure rises, such a flow rate regulator can adjust the volume of fluid flowing through per unit of time to a fixed maximum value.
Whereas the volume of fluid can be adjusted to a fixed maximum value when the inflowing fluid exhibits high pressure conditions, at low pressure conditions the control gap of the known flow rate regulators constitutes such a flow inhibitor that only comparatively small amounts of the fluid can flow through.
A sanitary insertion cartridge disclosed in U.S. Pat. No. 3,847,178 is implemented as a flow rate regulator and is insertable in a sanitary liquid line. In the exemplary embodiment shown therein in FIG. 13, this known insertion cartridge has a central regulating core, which is sleeve-shaped, and has a regulating profile, on its external circumference over which the water flow washes. The central regulating core encloses an elastic restrictor which delimits a control gap whose clear cross-section changes under the pressure of the liquid flowing between itself and the regulating profile provided on the external circumference of the sleeve-shaped regulating core, in such a way that the quantity of liquid flowing through per unit of time evens out and is regulated to a fixed maximum value. In order to avoid any irregularities in the low pressure range and in order to be able to provide a sufficient quantity of water, even in low pressure ranges, the sleeve inner chamber of the central regulating core is designed as a bypass channel, which has a valve in the area of its channel inlet. The valve moves under the pressure of the liquid flowing through from an open position, against the force of a reset spring, into the closed position. This bypass channel provides a larger light flow cross-section in lower pressure ranges; in relatively higher pressure ranges, the bypass channel is closed by the valve and the flow cross-section is limited to the control gap of the flow rate regulator.
The liquid jet does flow out of the flow rate regulator in U.S. Pat. No. 3,847,178, regulated to a fixed maximum value, but is otherwise uncontrolled. In order to shape the liquid jet into a homogeneous, non-splashing (and optionally also sparkling) soft water jet, a typical jet regulator is to be connected downstream from the flow rate regulator. Like jet regulators, flow rate regulators of this type are impaired in their function by the dirt particles entrained in the liquid, which may accumulate before or in the control gap of the flow rate regulator or in the jet divider of the jet regulator.